Qnap is some ubuntu linux station 2.0 thing which brags about their
"Linux Station, users can directly utilize various feature-rich Linux® apps, enjoying a private cloud that combines storage and IoT applications."
It's built on a older kernal lts 4.12
Someone at QNAP/ubun linux station made Clementine the default player
Maybe this
https://forum.qnap.com/Open the command line on linux station and type in clementine, which will start clem on the terminal for more detailed info about whatever the failure is